Cooling fan

ABSTRACT

A cooling fan includes a frame ( 100 ) and an impeller ( 200 ) having a plurality of blades ( 240 ) disposed in the frame ( 100 ). The frame ( 100 ) has a cap ( 120 ) with an air inlet ( 122 ), a base ( 140 ) and a sidewall ( 160 ) extending from a periphery of the base ( 140 ) with an air outlet ( 180 ) defined therein. The cap ( 120 ) is mounted on the sidewall ( 160 ) with a chamber formed between the cap ( 120 ), the base ( 140 ) and the sidewall ( 160 ). A curved tongue portion ( 190 ) is formed on the sidewall ( 160 ) in vicinity of the air outlet ( 180 ). A protrusion ( 124 ) is formed on the cap ( 120 ) in vicinity of the curved tongue portion ( 190 ) and protrudes into the air inlet ( 122 ).

CROSS REFERENCE

Relevant subject matter is disclosed in a pending U.S. patentapplication Ser. No. ______, filed on ______, and entitled “COOLINGFAN”, which is invented by the same inventors and assigned to the sameassignee as this application and which is hereby fully incorporated byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a cooling fan, and moreparticularly to a cooling fan having low noise.

2. Description of Related Art

The computer CPU speed has been greatly increased in recent years due toa rapid progress in semi-conductor technologies. The chip surface heatflux is thus higher and higher accordingly. It is becoming a criticalchallenge on how to remove the heat so that the system can run reliably.The compact space with high flow resistance in a notebook computerenvironment is even more critical in the heat removal. A fan with higherair pressure is frequently chosen under such a consideration.

A cooling fan in related art is shown in FIG. 3. The cooling fanincludes a frame 10 and an impeller 20 disposed in the frame 10. Theframe 10 includes air inlets 12, 14 matching the impeller 20 and an airoutlet. The impeller 20 includes a hub 22, a base plate 24 and aplurality of blades 26 formed thereon. The blades 26 transfer the intakeairflow parallel to the axial direction of the impeller 20 to theoutward airflow along the radial direction of the hub 22, and theoutward airflow is then expelled out of the air outlet. However, an airoutflow in a curved tongue portion 16 of the frame 10 will interferewith the intake airflow of the air inlets 12, 14 and the later airoutflow due to adverse airflow, creating many problems such as noise.

For the foregoing reasons, there is a need for a cooling fan which haslow noise.

SUMMARY OF THE INVENTION

A cooling fan comprises a frame and an impeller having a plurality ofblades disposed in the frame. The frame has a cap with an air inlet, abase and a sidewall extending from a periphery of the base with an airoutlet defined therein. The cap is mounted on the sidewall with achamber formed between the cap, the base and the sidewall. A curvedtongue portion is formed on the sidewall in vicinity of the air outlet.A protrusion is formed on the cap in vicinity of the curved tongueportion and protrudes into the air inlet.

Other advantages and novel features of the present invention will becomemore apparent from the following detailed description when taken inconjunction with the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present apparatus can be better understood withreference to the following drawings. The components in the drawings arenot necessarily drawn to scale, the emphasis instead being placed uponclearly illustrating the principles of the present apparatus. Moreover,in the drawings, like reference numerals designate corresponding partsthroughout the several views.

FIG. 1 is an assembled view of a cooling fan in accordance with apreferred embodiment of the present invention;

FIG. 2 is an exploded, isometric view of FIG. 1; and

FIG. 3 is an exploded, isometric view of a cooling fan in related art.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1-2, a cooling fan of a preferred embodiment of theinvention comprises a frame 100, and an impeller 200 disposed in theframe 100. The impeller 200 comprises a hub 220 and a plurality ofblades 240 mounted on the hub 220.

The frame 100 comprises a cap 120, a base 140, and a sidewall 160perpendicularly and upwardly extending from a periphery of the base 140.The cap 120 is mounted on the sidewall 160 with a chamber formed betweenthe cap 120, the base 140 and the sidewall 160. The impeller 200 isdisposed in the chamber to blow an outward airflow out of the chamberfrom an air outlet 180, which is defined in a front of the sidewall 160.A curved tongue portion 190 protrudes inwardly from the sidewall 160,and is adjacent to the air outlet 180 to adjust an intake airflowflowing into the frame 100.

The cap 120 and the base 140 respectively define a first air inlet 122and a second air inlet 142 therein. The air enters into the chamber viathe first and second air inlets 122, 142. The first and second airinlets 122, 142 both are round-shaped in profile. A protrusion 124 isformed on the cap 120 and protrudes into the first air inlet 122. Theprotrusion 124 is adjacent to the curved tongue portion 190, and servesto decrease the amount of intake airflow of the first air inlet 122 atthe curved tongue portion 190. Accordingly, the amount of an air outflowin vicinity of the curved tongue portion 190, which usually flows backto the air inlets 122, 142 to interfere with the intake airflow and thelater air outflow, is decreased. Therefore, the cooling fan has lownoise.

For further effectively decreasing the noise of the cooling fan, twovent holes 148 are defined in the base 140 adjacent to the curved tongueportion 190 and the protrusion 124. As shown in FIG. 2, the two ventholes 148 are defined between tip portions of the blades 240 and thesidewall 160 in vicinity of the curved tongue portion 190. The ventholes 148 serve to dissipate the air outflow in vicinity of the curvedtongue portion 190, which usually flows back to the air inlets 122, 142to interfere with the intake airflow and the later air outflow.Therefore, the noise of the cooling fan is further decreased.

As mentioned above, the protrusion 124 and the two vent holes 148 areformed in vicinity of the curved tongue portion 190, and suppress theadverse airflow in the airflow passage in vicinity of the curved tongueportion 190. As a result, the outward airflow of the air outlet 180 ismore balanced and the noise of the cooling fan is reduced.

In the above embodiment, the protrusion 124 is preferably arranged invicinity of the curved tongue portion 190 and the vent holes 148. Inanother embodiment, the protrusion may be arranged in another portion ofthe cap away from the curved tongue portion, so long as the amount ofintake airflow of the first air inlet is decreased.

Still for further effectively decreasing the noise of the cooling fan,another protrusion 144 is formed on the base 140 and protrudes into thesecond air inlet 142. The another protrusion 144 is in vicinity of thecurved tongue portion 190 and faces the protrusion 124 to decrease theamount of intake airflow of the second air inlet 142.

It is believed that the present invention and its advantages will beunderstood from the foregoing description, and it will be apparent thatvarious changes may be made thereto without departing from the spiritand scope of the invention or sacrificing all of its materialadvantages, the examples hereinbefore described merely being preferredor exemplary embodiments of the invention.

1. A cooling fan comprising: an impeller having a plurality of blades;and a frame having a cap with an air inlet, a base and a sidewallextending from a periphery of the base with an air outlet definedtherein; wherein the cap is mounted on the sidewall with a chamberformed between the cap, the base and the sidewall, and the impeller isdisposed in the chamber; wherein a curved tongue portion is formed onthe sidewall in vicinity of the air outlet and protrudes into thechamber; and wherein a protrusion is formed on the cap in vicinity ofthe curved tongue portion and protrudes into the air inlet.
 2. Thecooling fan as described in claim 1, wherein a vent hole is defined inthe base in vicinity of the curved tongue portion.
 3. The cooling fan asdescribed in claim 2, wherein the protrusion faces the vent hole.
 4. Thecooling fan as described in claim 2, wherein the vent hole is positionedbetween tips of the blades and the sidewall.
 5. The cooling fan asdescribed in claim 4, wherein the base has an air inlet defined therein,and another protrusion is formed on the base and protrudes into the airinlet of the base; the vent hole is positioned between the anotherprotrusion and the curved tongue portion.
 6. The cooling fan asdescribed in claim 1, wherein the base has an air inlet defined therein,and another protrusion is formed on the base and protrudes into the airinlet of the base.
 7. The cooling fan as described in claim 6, whereinthe protrusion and the another protrusion are aligned with each other.8. A cooling fan comprising: a frame comprising a chamber, an air inletand an air outlet communicated with the chamber, a protrusion formed onthe frame and protruded into the air inlet; and an impeller having aplurality of blades disposed in the chamber.
 9. The cooling fan asdescribed in claim 8, wherein another protrusion is formed on the frameand protrudes into another air inlet defined in the frame.
 10. Thecooling fan as described in claim 9, wherein the protrusion and theanother protrusion are aligned with each other.
 11. The cooling fan asdescribed in claim 8, wherein the frame comprises a cap, a base and asidewall extending from a periphery of the base, and the cap is mountedon the sidewall so that the chamber is formed between the cap, the baseand the sidewall; the air inlet is defined in the cap, and the airoutlet is defined in the sidewall.
 12. The cooling fan as described inclaim 11, wherein a curved tongue portion is formed on the sidewall invicinity of the air outlet.
 13. The cooling fan as described in claim12, wherein the protrusion is in vicinity of the curved tongue portion.14. The cooling fan as described in claim 12, wherein the protrusion isaway from the curved tongue portion.